Spine distraction implant and method

ABSTRACT

A spine distraction implant alleviates pain associated with spinal stenosis and facet arthropathy by expanding the volume in the spine canal and/or neural foramen. The implant provides a spinal extension stop while allowing freedom of spinal flexion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/732,589, entitled “Spine Distraction Implant,” filed Dec. 10, 2003,which is a divisional application of U.S. patent application Ser. No.09/842,756, entitled “Spine Distraction Implant,” filed Apr. 26, 2001,now U.S. Pat. No. 6,699,247, which is a continuation of U.S. patentapplication Ser. No. 09/474,038, entitled “Spine Distraction Implant,”filed Dec. 28, 1999, now U.S. Pat. No. 6,332,882, which is acontinuation of U.S. patent application Ser. No. 09/175,645, entitled“Spine Distraction Implant,” filed Oct. 20, 1998, now U.S. Pat. No.6,068,630, which is a continuation-in-part of U.S. patent applicationSer. No. 08/958,281, entitled “Spine Distraction Implant and Method,”filed Oct. 27, 1997, now U.S. Pat. No. 5,860,977, which is acontinuation-in-part of U.S. patent application Ser. No. 08/778,093,entitled “Spine Distraction Implant and Method,” filed Jan. 2, 1997, nowU.S. Pat. No. 5,836,948, each of which is incorporated herein byreference in its entirety.

BACKGROUND

As the present society ages, it is anticipated that there will be anincrease in adverse spinal conditions which are characteristic of olderpeople. By way of example, with aging comes increases in spinal stenosis(including but not limited to central canal and lateral stenosis), thethickening of the bones which make up the spinal column and facetarthropathy. Spinal stenosis is characterized by a reduction in theavailable space for the passage of blood vessels and nerves. Painassociated with such stenosis can be relieved by medication and/orsurgery. Of course, it is desirable to eliminate the need for majorsurgery for all individuals and in particular for the elderly.

Accordingly, there needs to be developed procedures and implants foralleviating such condition which are minimally invasive, can betolerated by the elderly and can be performed preferably on anoutpatient basis.

SUMMARY

The present invention is directed to providing a minimally invasiveimplant and method for alleviating discomfort associated with the spinalcolumn.

The present invention provides for apparatus and method for relievingpain by relieving the pressure and restrictions on the aforementionedblood vessels and nerves. Such alleviation of pressure is accomplishedin the present invention through the use of an implant and method whichdistract the spinous process of adjacent vertebra in order to alleviatethe problems caused by spinal stenosis and facet arthropathy and thelike. While the implant and method particularly address the needs of theelderly, the invention can be used with individuals of all ages andsizes where distraction of the spinous process would be beneficial.

In one aspect of the invention, an implant is provided for relievingpain comprising a device positioned between a first spinous process anda second spinous process. The device includes a spinal column extensionstop and a spinal column flexion non-inhibitor.

In another aspect of the invention, the implant is positioned betweenthe first spinous process and the second spinous process and includes adistraction wedge that can distract the first and second spinousprocesses as the implant is positioned between the spinous processes.

In yet another aspect of the present invention, the implant includes adevice which is adapted to increasing the volume of the spinal canaland/or the neural foramen as the device is positioned between adjacentspinous processes.

In yet a further aspect of the present invention, a method is presentedfor relieving pain due to the development of, by way of example only,spinal stenosis and facet arthropathy. The method is comprised of thesteps of accessing adjacent first and second spinal processes of thespinal column and distracting the processes a sufficient amount in orderto increase the volume of the spinal canal in order to relieve pain. Themethod further includes implanting a device in order to maintain theamount of distraction required to relieve such pain.

In yet a further aspect of the invention, the method includes implantinga device in order to achieve the desired distraction and to maintainthat distraction.

In yet a further aspect of the invention, the implant includes a firstportion and a second portion. The portions are urged together in orderto achieve the desired distraction.

In still a further aspect of the invention, the implant includes adistracting unit and a retaining unit. The distracting unit includes abody which can be urged between adjacent spinous processes. The bodyincludes a slot. After the distracting unit is positioned, the retainingunit can fit into the slot of the retaining unit and be secured thereto.

In yet a further aspect of the invention, the implant includes a firstunit with a central body. A sleeve is provided over the central body andis at least partially spaced from the central body in order to allow fordeflection toward the central body.

In a further aspect of the invention, the implant includes a first unithaving a central body with a guide and a first wing, with the first winglocated at first end of the body. The guide extends from a second end ofthe body located distally from the first wing. The implant furtherincludes a sleeve provided over said central body. The sleeve is atleast partially spaced from the central body in order to allow fordeflection of the sleeve toward the central body. The implant furtherincludes a second wing and a device for securing the second wing to thefirst unit, wherein the sleeve is located between the first and secondwings.

In yet another aspect of the invention, an implant system includes acylindrical sleeve which is inwardly deflectable. The system furtherincludes an insertion tool which includes an insertion guide, a centralbody, a stop and a handle. The guide and the stop extend from oppositesides of the central body and the handle extend from the stop. A sleevefits over the guide and against the stop preparatory to being positionedbetween the two adjacent vertebrae with the insertion tool.

In yet a further aspect of the invention, the implant includes centralbody and first and second wings and a means for selectively positioningone of the first and second wings relative to the other in order toaccommodate spinous processes of different sizes.

Other implants and methods within the spirit and scope of the inventioncan be used to increase the volume of the spinal canal therebyalleviating restrictions on vessels and nerves associated therewith, andpain.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 depict an embodiment of an implant of the invention whichis adjustable in order to select the amount of distraction required.FIG. 1 depicts the implant in a more extended configuration than doesFIG. 2.

FIGS. 3 a and 3 b depict side and end views of a first forked and of theembodiment of FIG. 1.

FIGS. 4 a and 4 b depict side sectioned and end views of an interbodypiece of the implant of FIG. 1.

FIGS. 5 a and 5 b depict side and end views of a second forked end ofthe embodiment of FIG. 1.

FIGS. 6, 7, 8, 9 and 10 depict apparatus and method for anotherembodiment of the present invention for creating distraction betweenadjacent spinous processes.

FIGS. 11, 12 and 13 depict yet a further embodiment of the invention forcreating distraction between adjacent spinous processes.

FIGS. 14 and 15 depict a further apparatus and method of an embodimentof the invention for creating distraction.

FIGS. 16, 16 a, and 17 depict yet another embodiment of the presentinvention.

FIGS. 18, 19 and 20 depict yet a further apparatus and method of thepresent embodiment.

FIGS. 21 and 22 depict still a further embodiment of the presentinvention.

FIGS. 23, 24 and 25 depict another embodiment of the present invention.

FIGS. 26, 27 and 28 depict another embodiment of the invention.

FIGS. 29 and 30 depict side elevational views of differently shapedimplants of embodiments of the present invention.

FIGS. 31, 32 and 33 depict various implant positions of an apparatus ofthe present invention.

FIGS. 34 and 35 depict yet another apparatus and method of the presentinvention.

FIGS. 36, 37 and 38 depict three different embodiments of the presentinvention.

FIGS. 39 and 40 depict yet another apparatus and method of an embodimentof the present invention.

FIGS. 41, 42 and 43 depict yet further embodiments of an apparatus andmethod of the present invention.

FIG. 44 is still a further embodiment of an implant of the invention.

FIG. 45 is yet another depiction of an apparatus and method of theinvention.

FIGS. 46 and 47 depict still a further apparatus and method of anembodiment of the invention.

FIGS. 48, 49, 50 and 51 depict yet a further apparatus and method of theinvention.

FIGS. 52, 53, 54, 55 a and 55 b depict another apparatus and method ofthe invention.

FIGS. 56, 57 and 58 depict yet a further apparatus and method of theinvention.

FIGS. 59 and 60 depict still a further embodiment of the invention.

FIG. 61 depict another embodiment of the invention.

FIGS. 62 and 63 depict yet another embodiment of the present invention.

FIGS. 64 and 65 depict still a further embodiment of the presentinvention.

FIG. 66 depicts another embodiment of the invention.

FIGS. 67 and 68 depict yet another embodiment of the present invention.

FIGS. 69, 70, 71 and 71 a depict a further embodiment of the presentinvention.

FIGS. 72 and 73 depict still another embodiment of the invention.

FIGS. 74, 75, 76, 77, and 78 depict still other embodiments of theinvention.

FIGS. 79, 80, 80 a, 81, 82, 83, 83 a, 84, 85, 86 and 87 depict still afurther embodiment of the present invention.

FIGS. 88, 89, 90 and 91 depict yet another embodiment of the presentinvention.

FIGS. 92, 92 a, 92 b, 93, 93 a, 93 b, 93 c, 93 d, 94, 94 a, 94 b, 95, 95a, and 96, depict still a further embodiment of the present inventionwherein a sleeve is provided which is capable of deflecting response torelative motion between the spinous processes.

FIG. 97 depicts still another embodiment of the present invention.

FIG. 98 depicts yet a further embodiment of the present invention.

FIGS. 99 and 100 depict still another embodiment of the presentinvention including an insertion tool.

FIGS. 101, 102, 102 a, 103, 104, 105, 106, and 107 depict still afurther embodiment of the present invention.

FIGS. 108, 109, and 110 depict still another embodiment of the presentinvention.

FIGS. 111, 112, 113, 114, 115, 116, and 117 depict yet anotherembodiment of the present invention.

FIG. 118 depicts a graph showing characteristics of a preferred materialusable with several of the embodiments of the present invention.

For simplicity in description, identical components are labeled by thesame numerals in this application.

DETAILED DESCRIPTION Embodiment of FIGS. 1-5 a, 5 b

A first embodiment of the invention is shown in FIGS. 1-5 a, 5 b.Implant 20 includes first and second forked ends 22 and 24, eachdefining a saddle 26, 28 respectively. The forked ends 22, 24 are matedusing an interbody piece 30. As can be seen in FIGS. 3 a, 3 b, the firstforked end 22 includes a threaded shaft 32 which projects rearwardlyfrom the saddle 26. The threaded shaft 32 fits into the threaded bore 34(FIG. 4 a) of the interbody piece 30.

The second forked end 24 (FIGS. 5 a, 5 b) includes a smooth cylindricalshaft 36 which can fit into the smooth bore 38 of the interbody piece30.

FIG. 1 shows the implant 20 in a fully extended position, while FIG. 2shows the implant in an unextended position. In the unextended position,it can be seen that the threaded shaft 32 of the first forked end 22fits inside the hollow cylindrical shaft 36 of the second forked end 24.

For purposes of implantation between adjacent first and second spinousprocesses of the spinal column, the implant 20 is configured as shown inFIG. 2. The first and second spinous processes are exposed usingappropriate surgical techniques and thereafter, the implant 20 ispositioned so that saddle 26 engages the first spinous process, andsaddle 28 engages the second spinous process. At this point, theinterbody piece 30 can be rotated by placing an appropriate tool or pininto the cross holes 40 and upon rotation, the saddle 26 is movedrelative to the saddle 28. Such rotation spreads apart or distracts thespinous processes with the resultant and beneficial effect of enlargingthe volume of the spinal canal in order to alleviate any restrictions onblood vessels and nerves.

It is noted that this implant as well as the several other implantsdescribed herein act as an extension stop. That means that as the backis bent backwardly and thereby placed in extension the spacing betweenadjacent spinous processes cannot be reduced to a distance less than thedistance between the lowest point of saddle 26 and the lowest point ofsaddle 28. This implant, however, does not inhibit or in any way limitthe flexion of the spinal column, wherein the spinal column is bentforward.

Preferably, such a device provides for distraction in the range of about5 mm to about 15 mm. However, devices which can distract up to and above22 mm may be used depending on the characteristics of the individualpatient.

With all the ligaments (such as the supraspinous ligament) and tissuesassociated with the spinous processes left intact, the implant 20 can beimplanted essentially floating in position in order to gain the benefitsof the aforementioned extension stop and flexion non-inhibitor. Ifdesired, one of the saddles 26 can be laterally pinned with pin 29 toone of the spinous processes and the other saddle can be looselyassociated with the other spinous processes by using a tether 31 whicheither pierces or surrounds the other spinous process and then isattached to the saddle in order to position the saddle relative to thespinous process. Alternatively, both saddles can be loosely tethered tothe adjacent spinous process in order to allow the saddles to moverelative to the spinous processes.

The shape of the saddles, being concave, gives the advantage ofdistributing the forces between the saddle and the respective spinousprocess. This ensures that the bone is not resorbed due to the placementof the implant 20 and that the structural integrity of the bone ismaintained.

The implant 20 in this embodiment can be made of a number of materials,including but not limited to, stainless steel, titanium, ceramics,plastics, elastics, composite materials or any combination of the above.In addition, the modulus of elasticity of the implant can be matched tothat of bone, so that the implant 20 is not too rigid. The flexibilityof the implant can further be enhanced by providing additional aperturesor perforations throughout the implant in addition to the holes 40 whichalso have the above stated purpose of allowing the interbody piece 30 tobe rotated in order to expand the distance between the saddle 26, 28.

In the present embodiment, it is understood that the spinous processescan be accessed and distracted initially using appropriateinstrumentation, and that the implant 20 can be inserted and adjusted inorder to maintain and achieve the desired distraction. Alternatively,the spinous process can be accessed and the implant 20 appropriatelypositioned. Once positioned, the length of the implant can be adjustedin order to distract the spinous processes or extend the distraction ofalready distracted spinous processes. Thus, the implant can be used tocreate a distraction or to maintain a distraction which has already beencreated.

The placement of implants such as implant 20 relative to the spinousprocess will be discussed herein with other embodiments. However, it isto be noted that ideally, the implant 20 would be placed close to theinstantaneous axis of rotation of the spinal column so that the forcesplaced on the implant 20 and the forces that the implant 20 places onthe spinal column are minimized.

Further, it is noted that during the actual process of installing orimplanting the implant 20, that the method uses the approach ofextending the length of the implant 20 a first amount and then allowingthe spine to creep or adjust to this distraction. Thereafter, implant 20would be lengthened another amount, followed by a period where the spineis allowed to creep or adjust to this new level of distraction. Thisprocess could be repeated until the desired amount of distraction hasbeen accomplished. This same method can be used with insertion toolsprior to the installation of an implant. The tools can be used to obtainthe desired distraction using a series of spinal distraction and spinecreep periods before an implant is installed.

Embodiment of FIGS. 6, 7, 8, 9 and 10

The embodiment of the invention shown in the above FIGS. 6, 7, 8, 9 and10 includes distraction or spreader tool 50 which has first and secondarms 52, 54. Arms 52, 54 are pivotal about pivot point 56 andreleaseable from pivot point 56 in order to effect the implantation ofimplant 58. As can be seen in FIG. 6, in cross-section, the arms 52, 54are somewhat concave in order to cradle and securely hold the firstspinous process 60 relative to arm 52 and the second spinous process 62relative to arm 54. The distraction tool 50 can be inserted through asmall incision in the back of the patient in order to address the spacebetween the first spinous process 60 and the second spinous process 62.Once the tool 50 is appropriately positioned, the arms 52, 54 can bespread apart in order to distract the spinous processes. After this hasoccurred, an implant 58 as shown in FIGS. 8 and 9, or of a design shownin other of the embodiments of this invention, can be urged between thearms 52, 54 and into position between the spinous processes. After thisoccurs, the arms 52, 54 can be withdrawn from the spinous processesleaving the implant 58 in place. The implant 58 is urged into placeusing a tool 64 which can be secured to the implant 58 through athreaded bore 66 in the back of the implant. As can be seen in FIG. 10,the implant 58 includes saddles 68 and 70 which cradle the upper andlower spinous processes 60, 62 in much the same manner as the abovefirst embodiment and also in much the same manner as the individual armsof the tool 50. The saddles as described above tend to distribute theload between the implant and the spinous processes and also assure thatthe spinous process is stably seated at the lowest point of therespective saddles.

Embodiment of FIGS. 11, 12 and 13

Another embodiment of the apparatus and method of the invention is shownin FIGS. 11, 12 and 13. In this embodiment, the spreader or distractiontool 80 includes first and second arms 82, 84 which are permanentlypivoted at pivot point 86. The arms include L-shaped ends 88, 90.Through a small incision, the L-shaped ends 88, 90 can be insertedbetween the first and second spinous processes 92, 94. Once positioned,the arms 82, 84 can be spread apart in order to distract the spinousprocesses. The implant 96 can then be urged between the spinousprocesses in order to maintain the distraction. It is noted that implant96 includes wedged surfaces or ramps 98, 100. As the implant 96 is beingurged between the spinous processes, the ramps further cause the spinousprocesses to be distracted. Once the implant 96 is fully implanted, thefull distraction is maintained by the planar surfaces 99, 101 locatedrearwardly of the ramps. It is to be understood that the cross-sectionof the implant 96 can be similar to that shown for implant 58 or similarto other implants in order to gain the advantages of load distributionand stability.

Embodiments of FIGS. 14, 15. 16, 16 a, and 17

In FIGS. 14 and 15, yet another embodiment of the invention is depicted.In this embodiment, the implant 110 includes first and second conicallyshaped members 112, 114. Member 112 includes a male snap connector 116and member 114 includes a female snap connector 118. With male snapconnector 116 urged into female snap connector 118, the first member 112is locked to the second member 114. In this embodiment, a distraction orspreader tool 80 could be used. Once the spinous process has been spreadapart, an implantation tool 120 can be used to position and snaptogether the implant 110. The first member 112 of implant 110 is mountedon one arm and second member 114 is mounted on the other arm of tool120. The member 112, 114 are placed on opposite sides of the spacebetween adjacent spinous processes. The members 112, 114 are urgedtogether so that the implant 110 is locked in place between the spinousprocesses as shown in FIG. 15. It is to be noted that the implant 110can also be made more self-distracting by causing the cylindricalsurface 122 to be more conical, much as surface 124 is conical, in orderto hold implant 110 in place relative to the spinous processes and alsoto create additional distraction.

An alternative embodiment of the implant can be seen in FIGS. 16 and 17.This implant 130 includes first and second members 132, 134. In thisparticular embodiment, the implants are held together using a screw (notshown) which is inserted through countersunk bore 136 and engages athreaded bore 138 of the second member 134. Surfaces 139 are flattened(FIG. 17) in order to carry and spread the load applied thereto by thespinous processes.

The embodiment of implant 130 is not circular in overall outsideappearance, as is the embodiment 110 of FIGS. 14 and 15. In particular,with respect to the embodiment of implant 130 of FIGS. 16 and 17, thisembodiment is truncated so that the lateral side 140, 142 are flattenedwith the upper and lower sides 144, 146 being elongated in order tocapture and create a saddle for the upper and lower spinous processes.The upper and lower sides, 144, 146 are rounded to provide a moreanatomical implant which is compatible with the spinous processes.

If it is desired, and in order to assure that the first member 132 andthe second member 134 are aligned, key 148 and keyway 150 are designedto mate in a particular manner. Key 148 includes at least one flattenedsurface, such as flattened surface 152, which mates to an appropriatelyflattened surface 154 of the keyway 150. In this manner, the firstmember is appropriately mated to the second member in order to formappropriate upper and lower saddles holding the implant 130 relative tothe upper and lower spinous processes.

FIG. 16 a depicts second member 134 in combination with a rounded noselead-in plug 135. Lead-in plug 135 includes a bore 137 which can fitsnugly over key 148. In this configuration, the lead-in plug 135 can beused to assist in the placement of the second member 134 between spinousprocesses. Once the second member 134 is appropriately positioned, thelead-in plug 135 can be removed. It is to be understood that the lead-inplug 135 can have other shapes such as pyramids and cones to assist inurging apart the spinous processes and soft tissues in order to positionthe second member 134.

Embodiment of FIGS. 18, 19 and 20

The implant 330 as shown in FIG. 18 is comprised of first and secondmating wedges 332 and 334. In order to implant these wedges 332, 334,the spinous processes are accessed from both sides and then a tool isused to push the wedges towards each other. As the wedges are urgedtowards each other, the wedges move relative to each other so that thecombined dimension of the implant 330 located between the upper andlower spinous processes 336, 338 (FIG. 20), increases, therebydistracting the spinous processes. It is noted that the wedges 332, 334include saddle 340, 342, which receiving the spinous processes 336, 338.These saddles have the advantages as described hereinabove.

The first or second wedges 332, 334 have a mating arrangement whichincludes a channel 344 and a projection of 346 which can be urged intothe channel in order to lock the wedges 332, 334 together. The channel334 is undercut in order to keep the projection from separatingtherefrom. Further, as in other devices described herein, a detent canbe located in one of the channel and the projection, with acomplimentary recess in the other of the channel and the projection.Once these two snap together, the wedges are prevented from slidingrelative to the other in the channel 344.

While the above embodiment was described with respect to wedges, thewedges could also have been designed substantially as cones with all thesame features and advantages.

Embodiments of FIGS. 21 and 22

The implant 370 is comprised of first and second distraction cone 372,374. These cones are made of a flexible material. The cones arepositioned on either side of the spinous processes 376, 378 as shown inFIG. 21. Using appropriate tool as shown hereinabove, the distractioncones 372, 374 are urged together. As they are urged together, the conesdistract the spinous processes as shown in FIG. 22. Once this hasoccurred, an appropriate screw or other type of fastening mechanism 380can be used to maintain the position of the distraction cones 372, 374.The advantage of this arrangement is that the implant 370 isself-distracting and also that the implant, being flexible, molds aboutthe spinous processes as shown in FIG. 22.

Embodiments of FIGS. 23, 24 and 25

In FIGS. 23 and 24, another embodiment of the implant 170 is depicted.This implant is guided in place using an L-shaped guide 172 which canhave a concave cross-section such as the cross-section 52 of retractiontool 50 in FIG. 6 in order to cradle and guide the implant 170 inposition. Preferably a small incision would be made into the back of thepatient and the L-shaped guide tool 172 inserted between the adjacentspinous processes. The implant 170 would be mounted on the end ofinsertion tool 174 and urged into position between the spinousprocesses. The act of urging the implant into position could cause thespinous processes to be further distracted if that is required. Prior tothe insertion of the L-shaped guide tool 172, a distraction tool such asshown in FIG. 13 could be used to initially distract the spinousprocesses.

Implant 170 can be made of a deformable material so that it can be urgedinto place and so that it can somewhat conform to the shape of the upperand lower spinous processes. This deformable material would bepreferably an elastic material. The advantage of such a material wouldbe that the load forces between the implant and the spinous processeswould be distributed over a much broader surface area. Further, theimplant would mold itself to an irregular spinous process shape in orderto locate the implant relative to spinous processes.

With respect to FIG. 25, this implant 176 can be inserted over a guidewire, guide tool or stylet 178. Initially, the guide wire 178 ispositioned through a small incision to the back of the patient to aposition between the adjacent spinous processes. After this hasoccurred, the implant is threaded over the guide wire 178 and urged intoposition between the spinous processes. This urging can further distractthe spinous processes if further distraction is required. Once theimplant is in place, the guide tool 178 is removed and the incisionclosed. The insertion tools of FIGS. 23 and 24 can also be used ifdesired.

Embodiment of FIGS. 26, 27 and 28

The embodiment shown in FIGS. 26, 27 and 28 uses an implant similar tothat depicted in FIGS. 8 and 9 with different insertion tools. As can beseen in FIG. 26, an L-shaped distraction tool 190 is similar to L-shapeddistraction tool 80 (FIG. 12), is used to distract the first and secondspinous processes 192, 194. After this has occurred, an insertion tool196 is placed between the spinous processes 192, 194. Insertion tool 196includes a handle 198 to which is mounted a square-shaped ring 200.

The distraction tool 190 can be inserted through a small incision in theback in order to spread apart the spinous processes. Through the sameincision which has been slightly enlarged laterally, an upper end 202 ofring 200 can be initially inserted followed by the remainder of the ring200. Once the ring is inserted, the ring can be rotated slightly bymoving handle 198 downwardly in order to further wedge the spinousprocesses apart. Once this has been accomplished, an implant such asimplant 204 can be inserted through the ring and properly positionedusing implant handle 206. Thereafter, the implant handle 206 and theinsertion tool 196 can be removed.

Embodiments of FIGS. 29, 30, 31, 32 and 33

As can be seen in FIGS. 29 and 30, the implants 210, 212, can havedifferent shapes when viewed from the side. These implants are similarto the above-referenced implants 58 (FIG. 8) and 204 (FIG. 28). Theseimplants have cross-sections similar to that shown in FIG. 10 whichincludes saddles in order to receive and hold the adjacent spinousprocesses.

As can be seen in FIGS. 31, 32 and 33, these implants can be placed indifferent positions with respect to the spinous process 214. Preferablyas shown in FIG. 33, the implant 210 is placed closest to the lamina216. Being so positioned, the implant 210 is close to the instantaneousaxis of rotation 218 of the spinal column, and the implant wouldexperience least forces caused by movement of the spine. Thus,theoretically, this is the optimal location for the implant.

As can be seen in FIGS. 31 and 32, the implant can be placed midwayalong the spinous process (FIG. 32) and towards the posterior aspect ofthe spinous process (FIG. 31). As positioned shown in FIG. 31, thegreatest force would be placed on the implant 210 due to a combinationof compression and extension of the spinal column.

Embodiment of FIGS. 34 and 35

Another embodiment of the invention is shown in FIGS. 34 and 35. Inthese figures, implant 220 is comprised of a plurality of individualleaves 222 which are substantially V-shaped. The leaves includeinterlocking indentations or detents 224. That is, each leaf includes anindentation with a corresponding protrusion such that a protrusion ofone leaf mates with an indentation of an adjacent leaf. Also associatedwith this embodiment is an insertion tool 226 which has a blunt end 228which conforms to the shape of an individual leaf 222. For insertion ofthis implant into the space between the spinous processes as shown inFIG. 29, the insertion tool 226 first insert a single leaf 220. Afterthat has occurred, the insertion tool then inserts a second leaf withthe protrusion 224 of the second leaf snapping into correspondingindentation made by the protrusion 224 of the first leaf. This processwould reoccur with third and subsequent leaves until the appropriatespacing between the spinous processes was built up. As can be seen inFIG. 29, the lateral edges 229 of the individual leaves 222 are slightlycurved upwardly in order to form a saddle for receiving the upper andlower spinous processes.

Embodiments of FIGS. 36, 37 and 38

The embodiments of FIGS. 36, 37 and 38 which include implants 230, 232,and 234 respectively, are designed in such a manner so the implant locksitself into position once it is properly positioned between the spinousprocesses. Implant 220 is essentially a series of truncated cones andincludes a plurality of ever expanding steps 236. These steps are formedby the conical bodies starting with the nose body 238 followed therebehind by conical body 240. Essentially, the implant 234 looks like afir tree placed on its side.

The implant 230 is inserted laterally throughout the opening betweenupper and lower spinous processes. The first body 238 causes the initialdistraction. Each successive conical body distracts the spinousprocesses a further incremental amount. When the desired distraction hasbeen reached, the spinous processes are locked into position by steps236. At this point, if desired, the initial nose body 238 of the implantand other bodies 240 can be broken, snapped or sawed off if desired inorder to minimize the size of the implant 230. In order for a portion ofthe implant 230 to be broken or snapped off, the intersection betweenbodies such as body 238 and 240, which is intersection line 242, wouldbe somewhat weaken with the appropriate removal of material. It is notedthat only the intersection lines of the initial conical bodies need tobe so weakened. Thus, intersection line 244 between the bodies whichremain between the spinous processes would not need to be weaker, asthere would be no intention that the implant would be broken off at thispoint.

FIG. 37 shows implant 232 positioned between upper and lower spinousprocesses. This implant is wedge-shaped or triangular shaped incross-sectioned and includes bore pluralities 245 and 246. Through thesebores can be placed locking pins 248 and 250. The triangular orwedged-shaped implant can be urged laterally between and thus distractthe upper and lower spinous processes. Once the appropriate distractionis reached, pins 248, 250 can be inserted through the appropriate boresof the bore pluralities 245 and 246 in order to lock the spinousprocesses in a V-shaped valley formed by pins 248, 250 on the one handand the ramped surface 233, 235 on the other hand.

Turning to FIG. 38, the implant 234 has a triangular-shaped orwedge-shaped body similar to that shown in FIG. 32. In this embodiment,tab 252, 254 are pivotally mounted to the triangular shaped body 234.Once the implant 234 is appropriately positioned in order to distractthe spinous processes to the desired amount, the tabs 252, 254 rotateinto position in order to hold the implant 234 in the appropriateposition.

Embodiment of FIGS. 39 and 40

In the embodiment of FIGS. 39 and 40, cannula 258 is inserted through asmall incision to a position between upper and lower spinous processes.Once the cannula is properly inserted, an implant 260 is pushed throughthe cannula 258 using an insertion tool 262. The implant 260 includes aplurality of ribs or indentation 264 that assist in positioning theimplant 260 relative to the upper and lower spinal processes. Once theimplant 260 is in position, the cannula 258 is withdrawn so that theimplant 260 comes in contact with and wedges between the spinousprocesses. The cannula 258 is somewhat conical in shape with the noseend 266 being somewhat smaller than the distal end 268 in order toeffect the insertion of the cannula into the space between the spinousprocesses.

Further, a plurality of cannula can be used instead of one, with eachcannula being slightly bigger than one before. In the method of theinvention, the first smaller cannula would be inserted followed bysuccessively larger cannula being placed over the previous smallercannula. The smaller cannula would then be withdrawn from the center ofthe larger cannula. Once the largest cannula is in place, and theopening of the skin accordingly expanded, the implant, which isaccommodated by only the larger cannula, is inserted through the largercannula and into position.

Embodiments of FIGS. 41, 42 and 43

The precurved implant 270 in FIGS. 41 and 42, and precurved implant 272in FIG. 43 have common introduction techniques which includes a guidewire, guide tool, or stylet 274. For both embodiments, the guide wire274 is appropriately positioned through the skin of the patient and intothe space between the spinous processes. After this is accomplished, theimplant is directed over the guide wire and into position between thespinous processes. The precurved nature of the implant assist in (1)positioning the implant through a first small incision in the patient'sskin on one side of the space between two spinous processes and (2)guiding the implant toward a second small incision in the patient's skinon the other side of the space between the two spinous processes. Withrespect to the implant 270, the implant includes a conical introductionnose 276 and a distal portion 278. As the nose 276 is inserted betweenthe spinous processes, this causes distraction of the spinous processes.Break lines 280, 282 are established at opposite sides of the implant270. Once the implant is properly positioned over the guide wire betweenthe spinous processes, the nose portion 276 and the distal portion 278can be broken off along the break lines, through the above twoincisions, in order to leave the implant 270 in position.

Although only two break lines 280, 282 are depicted, multiple breaklines can be provided on implant 270 so that the implant can continue tobe fed over the guide wire 278 until the appropriate width of theimplant 270 creates the desired amount of distraction. As describedhereinabove, the break lines can be created by perforating or otherwiseweakening the implant 270 so that the appropriate portions can besnapped or sawed off.

With respect to the precurved implant 272, this implant is similar indesign to the implant 230 shown in FIG. 36. This implant 272 in FIG. 47,however, is precurved and inserted over a guide wire 274 to a positionbetween the spinous processes. As with implant 230 in FIG. 43, once theappropriate level of this distraction has been reached and if desired,sections of the implant 272 can be broken, snapped or sawed off asdescribed hereinabove in order to leave a portion of the implant wedgedbetween the upper and lower spinous processes.

Embodiment of FIG. 44

A further embodiment of the invention is shown in FIG. 44. Thisembodiment includes a combination insertion tool and implant 290. Theinsertion tool and implant 290 is in the shape of a ring which is hingedat point 292. The ring is formed by a first elongated and conicallyshaped member 294 and a second elongated and conically shaped member296. Members 294 and 296 terminate in points and through the use ofhinge 292 are aligned and meet. Through similar incisions on both sidesof the spinous processes, first member and second member are insertedthrough the skins of the patient and are mated together between thespinous processes. After this has occurred, the implant 290 is rotated,for example clockwise, so that increasingly widening portions of thefirst member 292 are used to distract the first and second spinousprocesses. When the appropriate level of distraction has occurred, theremainder of the ring before and after the section which is locatedbetween the spinous processes can be broken off as taught hereinabove inorder to maintain the desired distraction. Alternatively, with a smallenough ring, the entire ring can be left in place with the spinousprocesses distracted.

Embodiment of FIG. 45

In FIG. 45, the implant 300 is comprised of a plurality of rods orstylets 302 which are inserted between the upper and lower spinousprocesses. The rods are designed much as described hereinabove so thatthey may be broken, snapped or cut off. Once these are inserted and theappropriate distraction has been reached, the stylets are broken off anda segment of each stylet remains in order to maintain distraction of thespinous process.

Embodiment of FIGS. 46 and 47

Implant 310 of FIGS. 46 and 47 is comprised of a shape memory materialwhich coils upon being released. The material is straightened out in adelivery tool 312. The delivery tool is in position between upper andlower spinous processes 314, 316. The material is then pushed throughthe delivery tool. As it is released from the delivery end 318 of thedelivery tool, the material coils, distracting the spinous processes tothe desired amount. Once this distraction has been achieved, thematerial is cut and the delivery tool removed.

Embodiments of FIGS. 48, 49, 50 and 51

As can be seen in FIG. 48, the implant 320 is delivered between upperand lower spinous processes 322 and 324, by delivery tool 326. Once theimplant 320 is in place between the spinous processes, the delivery toolis given a 90° twist so that the implant goes from the orientation asshown in FIG. 49, with longest dimension substantially perpendicular tothe spinous processes, to the orientation shown in FIG. 50 where thelongest dimension is in line with and parallel to the spinous processes.This rotation causes the desired distraction between the spinousprocesses. Implant 320 includes opposed recesses 321 and 323 located atthe ends thereof. Rotation of the implant 320 causes the spinousprocesses to become lodged in these recesses.

Alternatively, the insertion tool 326 can be used to insert multipleimplants 320, 321 into the space between the spinous processes 322, 324(FIG. 51). Multiple implants 320, 321 can be inserted until theappropriate amount of distraction is built up. It is to be understood inthis situation that one implant would lock to another implant by use of,for example, a channel arrangement wherein a projection from one of theimplants would be received into and locked into a channel of the otherimplant. Such a channel arrangement is depicted with respect to theother embodiment.

Embodiment of FIGS. 52, 53, 54, 55 a and 55 b

The embodiment of FIGS. 52 through 55 b is comprised of a fluid-filleddynamic distraction implant 350. This implant includes a membrane 352which is placed over pre-bent insertion rod 354 and then insertedthrough an incision on one side of the spinous process 356. The bentinsertion rod, with the implant 350 thereover, is guided betweenappropriate spinous processes. After this occurs, the insertion rod 354is removed leaving the flexible implant in place. The implant 350 isthen connected to a source of fluid (gas, liquid, gel and the like) andthe fluid is forced into the implant causing it to expand as shown inFIG. 54, distracting the spinal processes to the desired amount. Oncethe desired amount of distraction has occurred, the implant 350 isclosed off as is shown in FIG. 55 a. The implant 350 being flexible, canmold to the spinous processes which may be of irregular shape, thusassuring positioning. Further, implant 350 acts as a shock absorber,damping forces and stresses between the implant and the spinousprocesses.

A variety of materials can be used to make the implant and the fluidwhich is forced into the implant. By way of example only, viscoelasticsubstances such as methylcellulose, or hyaluronic acid can be used tofill the implant. Further, materials which are initially a fluid, butlater solidify, can be inserted in order to cause the necessarydistraction. As the materials solidify, they mold into a custom shapeabout the spinous processes and accordingly are held in position atleast with respect to one of two adjacent spinous processes. Thus, itcan be appreciated that using this embodiment and appropriate insertiontools the implant can be formed about one spinous process in such amanner that the implant stays positioned with respect to that spinousprocess (FIG. 55 b). With such an embodiment, a single implant can beused as an extension stop for spinous process located on either side,without restricting flexion of the spinal column.

It is to be understood that many of the other implants disclosed hereincan be modified so that they receive a fluid in order to establish andmaintain a desired distraction much in the manner as implant 350receives a fluid.

Embodiment of FIGS. 56, 57 and 58

The implant 360 as shown in FIG. 56 is comprised of a shape memorymaterial such as a plastic or a metal. A curved introductory tool 362 ispositioned between the appropriate spinous processes as describedhereinabove. Once this has occurred, bore 364 of the implant is receivedover the tool. This act can cause the implant to straighten out. Theimplant is then urged into position and thereby distracts the spinousprocesses. When this has occurred, the insertion tool 362 is removed,allowing the implant to assume its pre-straightened configuration and isthereby secured about one of the spinous processes. Such an arrangementallows for an implant that is an extension stop and does not inhibitflexion of the spinous column. Alternatively, the implant can betemperature sensitive. That is to say that the implant would be morestraightened initially, but become more curved when it was warmed by thetemperature of the patient's body.

Embodiments of FIGS. 59 and 60

In this embodiment, the implant 380 is comprised of a plurality ofinterlocking leaves 382. Initially, a first leaf is positioned betweenopposed spinous processes 384, 386. Then subsequently, leafs 382 areinterposed between the spinous processes until the desired distractionhas been built up. The leaves are somewhat spring-like in order toabsorb the shock and can somewhat conform to the spinous processes.

Embodiment of FIG. 61

The implant 390 of FIG. 61 includes the placement of shields 392, 394over adjacent spinous processes 396, 398. The shields are used toprevent damage to the spinous processes. These shields include apertureswhich receives a self-tapping screw 400, 402. In practice, the shieldsare affixed to the spinous processes and the spinous processes aredistracted in the appropriate amount. Once this has occurred, a rod 404is used to hold the distracted position by being screwed into each ofthe spinous processes through the aperture in the shields using thescrews as depicted in FIG. 61.

Embodiment of FIGS. 62 and 63

Implant 410 of FIGS. 62, 63 is comprised of first and second members412, 414 which can be mated together using an appropriate screw andthreaded bore arrangement to form the implant 410. Main member 412 andmating member 414 form implant 410. Accordingly, the implant 410 wouldhave a plurality of members 414 for use with a standardized first member412. FIGS. 62 and 64 show different types of mating members 414. In FIG.62, the mating member 414 includes projections 416 and 418 which actlike shims. These projections are used to project into the space ofsaddles 420, 422 of the first member 412. These projections 416, 418 canbe of varying lengths in order to accommodate different sizes of spinousprocesses. A groove 424 is placed between the projections 416, 418 andmates with an extension 426 of the first member 412.

As shown in FIG. 63, the projections of the embodiment shown in FIG. 62are removed and recesses 428, 430 are substituted therefor. Theserecesses expand the area of the saddles 420, 422 in order to accommodatelarger spinous processes.

Embodiment of FIGS. 64, 65 and 66

The embodiments of FIGS. 64, 65 and 66 are similar in design and conceptto the embodiment of FIGS. 62 and 63. In FIG. 64, the implant 500includes the first and second members 502, 504. These members can besecured together with appropriate screws or other fastening means astaught in other embodiments. Implant 500 includes first and secondsaddles 506, 508 which are formed between the ends of first and secondmembers 502, 504. These saddles 506, 508 are used to receive and cradlethe adjacent spinous processes. As can be seen in FIG. 64, each saddle506, 508 is defined by a single projection or leg 510, 512, whichextends from the appropriate first and second members 502, 504. Unlikethe embodiment found in FIGS. 62 and 63, each of the saddles is definedby only a single leg as the ligaments and other tissues associated withthe spinous processes can be used to ensure that the implant is held inan appropriate position. With the configuration of FIG. 64, it is easierto position the implant relative to the spinous processes as each saddleis defined by only a single leg and thus the first and second memberscan be more easily worked into position between the various tissues.

In the embodiment of FIG. 65, the implant 520 is comprised of a singlepiece having saddles 522 and 524. The saddles are defined by a singleleg 526, 528 respectively. In order for this implant 520 to bepositioned between the spinous processes, an incision is made betweenlateral sides of adjacent spinous processes. The single leg 526 isdirected through the incision to a position adjacent to an oppositelateral side of the spinous process with the spinous process cradled inthe saddle 522. The spinous processes are then urged apart until saddle524 can be pivoted into position into engagement with the other spinousprocess in order to maintain the distraction between the two adjacentspinous processes.

The embodiment of FIG. 66 is similar to that of FIG. 65 with an implant530 and first and second saddles 532 and 534. Associated with eachsaddle is a tether 536, 538 respectively. The tethers are made offlexible materials known in the trade and industry and are positionedthrough bores in the implant 530. Once appropriately positioned, thetethers can be tied off. It is to be understood that the tethers are notmeant to be used to immobilize one spinous process relative to theother, but are used to guide motion of the spinous processes relative toeach other so that the implant 530 can be used as an extension stop anda flexion non-inhibitor. In other words, the saddles 532, 534 are usedto stop spinal column backward bending and extension. However, thetethers do not inhibit forward bending and spinal column flexion.

Embodiments of FIGS. 67, 68

The implant 550 is Z-shaped and includes a central body 552 and firstand second arms 554, 556, extending in opposite directions therefrom.The central body 552 of the implant 550 includes first and secondsaddles 558 and 560. The first and second saddles 558 and 560 wouldreceive upper and lower spinous processes 562, 568. The arms 554, 556are accordingly located adjacent the distal end 566 (FIG. 68) of thecentral body 552. The first and second arms 554, 556, act to inhibitforward movement, migration or slippage of the implant 550 toward thespinal canal and keep the implant in place relative to the first andsecond spinal processes. This prevents the implant from pressing down onthe ligamentum flavum and the dura. In a preferred embodiment, thecentral body would have a height of about 10 mm with each of the arms554, 556 have a height of also about 10 mm. Depending on the patient,the height of the body could vary from about less than 10 mm to aboutgreater than 24 mm. As can be seen in FIGS. 67 and 68, the first andsecond arms 554, 556 are additionally contoured in order to accept theupper and lower spinous processes 556, 558. In particular, the arms 554,556 as can be seen with respect to arm 554 have a slightly outwardlybowed portion 568 (FIG. 68) with a distal end 570 which is slightlyinwardly bowed. This configuration allows the arm to fit about thespinous process with the distal end 570 somewhat urged against thespinous process in order to guide the motion of the spinous processrelative to the implant. These arms 554, 556 could if desired to be mademore flexible than the central body 552 by making arms 554, 556 thinand/or with perforations, and/or other material different than that ofthe central body 550. As with the last embodiment, this embodiment canbe urged into position between adjacent spinous processes by directingan arm into a lateral incision so that the central body 552 can befinally positioned between spinous processes.

Embodiment of FIGS. 69, 70, 71 and 71 a

FIGS. 69, 70 and 71 are perspective front, end, and side views ofimplant 580 of the invention. This implant includes a central body 582which has first and second saddles 584, 586 for receiving adjacentspinous processes. Additionally, the implant 580 includes first andsecond arms 588 and 590. The arms, as with the past embodiment, preventforward migration or slippage of the implant toward the spinal canal.First arm 588 projects outwardly from the first saddle 584 and secondarm 590 projects outwardly from the second saddle 586. In a preferredembodiment, the first arm 588 is located adjacent to the distal end 600of the central body 582 and proceeds only partly along the length of thecentral body 582. The first arm 588 is substantially perpendicular tothe central body as shown in FIG. 70. Further, the first arm 588, aswell as the second arm 590, is anatomically rounded.

The second arm 590, projecting from second saddle 586, is locatedsomewhat rearward of the distal end 600, and extends partially along thelength of the central body 582. The second arm 590 projects at acompound angle from the central body 582. As can be seen in FIGS. 70 and71, the second arm 590 is shown to be at about an angle of 45° from thesaddle 586 (FIG. 70). Additionally, the second arm 590 is at an angle ofabout 45° relative to the length of the central body 580 as shown inFIG. 71. It is to be understood that other compound angles are withinthe spirit and scope of the invention as claimed.

In a preferred embodiment, the first and second arms 588, 590 have alength which is about the same as the width of the central body 582.Preferably, the length of each arm is about 10 mm and the width of thecentral body is about 10 mm. However, the bodies with the widths of 24mm and greater are within the spirit and scope of the invention, alongwith first and second arms ranging from about 10 mm to greater thanabout 24 mm. Further, it is contemplated that the embodiment couldinclude a central body having a width of about or greater than 24 mmwith arms being at about 10 mm.

It is to be understood that the embodiment of FIGS. 69, 70 and 71 aswell as the embodiment of FIGS. 67 and 68 are designed to preferably bepositioned between the L4-L5 and the L5-S1 vertebral pairs. Theembodiment of FIGS. 69, 70, 71 is particularly designed for the L5-S1position with the arms being designed to conform to the sloping surfacesfound therebetween. The first and second arms are thus contoured so thatthey lie flat against the lamina of the vertebra which has a slightangle.

The embodiment of FIGS. 69, 70, and 71 as with the embodiment of FIGS.67 and 68 is Z-shaped in configuration so that it may be inserted fromone lateral side to a position between adjacent spinous processes. Afirst arm, followed by the central body, is guided through the spacebetween the spinous processes. Such an arrangement only requires that aincision on one side of the spinous process be made in order tosuccessfully implant the device between the two spinous processes.

The implant 610 of FIG. 71 a is similar to that immediately above withthe first arm 612 located on the same side of the implant as the secondarm 614. The first and second saddle 616, 618 are slightly modified inthat distal portion 620, 622 are somewhat flattened from the normalsaddle shape in order to allow the implant to be positioned between thespinous processes from one side. Once in position, the ligaments andtissues associated with the spinous processes would hold the implantinto position. Tethers also could be used if desired.

Embodiment of FIGS. 72, 73

Implant 630 is also designed so that it can be inserted from one side ofadjacent spinous processes. This insert 630 includes a central body 632with the first and second arms 634, 636 extending on either sidethereof. As can be seen in FIG. 72, a plunger 638 is positioned toextend from an end of the central body 632. As shown in FIG. 72, theplunger 638 is fully extended and as shown in FIG. 73, the plunger 638is received within the central body 632 of the implant 630. With theplunger received into the implant 632, the third and fourth arms orhooks 640, 642 can extend outwardly from the central body 632. The thirdand fourth arms or hooks 640, 642 can be comprised of a variety ofmaterials, such as for example, shape memory metal materials ormaterials which have a springy quality.

For purposes of positioning the implant 630 between adjacent spinousprocesses, the plunger 638 is pulled outwardly as shown in FIG. 72. Thecentral body 632 is then positioned between adjacent spinous processesand the plunger 638 is allowed to move to the position of FIG. 73 sothat the third and fourth arms 640, 642 can project outwardly from thecentral body 632 in order to hold the implant 630 in position betweenthe spinous processes.

Plunger 638 can be spring biased to the position as shown in FIG. 73 orcan include detents or other mechanisms which lock it into thatposition. Further, the third and fourth arms themselves, as deployed,can keep the plunger in the position as shown in FIG. 73.

Embodiments of FIGS. 74, 75, 76, 77, and 78

Other embodiments of the invention are shown in FIGS. 74 through 78.FIGS. 74, 75 and 76 disclose implant 700. Implant 700 is particularlysuited for implantation between the L4-L5 and L5-S1 vertebra. As can beseen in FIG. 74, the implant 700 includes a central body 702 which has abore 704 provided therein. Bore 704 is used in order to adjust themodulus of elasticity of the implant so that it is preferablyapproximately two times the anatomical load placed on the vertebra inextension. In other words, the implant 700 is approximately two timesstiffer than the normal load placed on the implant. Such an arrangementis made in order to ensure that the implant is somewhat flexible inorder to reduce potential resorption of the bone adjacent to theimplant. Other modulus values can be used and be within the spirit ofthe invention.

Implant 700 includes first and second saddle 706, 708 which are used toreceive and spread the load from the upper and lower spinous processes.The saddle 706 is defined by first and second arms 710 and 712. Thesecond saddle 708 is defined by third and fourth arms 714 and 716. Ascan be seen in FIG. 74, the first arm 710, in a preferred embodiment, isapproximately two times the length of the body 702 with the second armbeing approximately less than a quarter length of the body. Third arm714 is approximately one times the length of the body 702 with thefourth arm 716 being, in this preferred embodiment, approximately oneand a half times the length of the body 702. The arms are designed insuch a way that the implant (1) can be easily and conveniently insertedbetween the adjacent spinous processes, (2) will not migrate forwardlytoward the spinal canal, and (3) will hold its position through flexionand extension as well as lateral bending of the spinal column.

First arm 710 is in addition designed to accommodate the shape of thevertebra. As can be seen in FIG. 74, the first arm 710 becomes narroweras it extends away from the body 702. The first arm 710 includes asloping portion 718 followed by a small recess 720 ending in a roundedportion 722 adjacent to the end 724. This design is provided toaccommodate the anatomical form of for example the L4 vertebra. It is tobe understood that these vertebra have a number of surfaces at roughly30° angles and that the sloping surfaces of this embodiment and theembodiments shown in FIGS. 77 and 78 are designed to accommodate thesesurfaces. These embodiments can be further modified in order toaccommodate other angles and shapes.

The second arm 712 is small so that it is easy to insert between thespinous processes, yet still define the saddle 706. The fourth arm 716is larger than the third arm 714, both of which are smaller than thefirst arm 710. The third and fourth arms are designed so that theydefine the saddle 706, guide the spinous processes relative to theimplant 700 during movement of the spinal column, and yet are of a sizewhich makes the implant easy to position between the spinous processes.

The procedure, by way of example only, for implanting the implant 700can be to make an incision laterally between two spinous processes andthen initially insert first arm 710 between the spinous processes. Theimplant and/or appropriate tools would be used to distract the spinousprocesses allowing the third leg 714 and the central body 702 to fitthrough the space between the spinous processes. The third leg 714 wouldthen come to rest adjacent the lower spinous processes on the oppositeside with the spinous processes resting in the first and second saddle706, 708. The longer fourth leg 716 would then assist in the positioningof the implant 700.

FIG. 77 includes an implant 740 which is similar to implant 700 and thushave similar numbering. The saddle 706, 708 of implant 740 have beencantered or sloped in order to accommodate the bone structure between,by way of example, the L4-L5 and the L5-S1 vertebra. As indicated above,the vertebra in this area have a number of sloping surfaces in the rangeof about 30°. Accordingly, saddle 706 is sloped at less than 30° andpreferably about 20° while saddle 708 is sloped at about 30° andpreferably more than 30°.

The implant 760 as shown in FIG. 78 is similar to implant 700 in FIG. 74and is similarly numbered. Implant 760 includes third and fourth legs714, 716 which have sloping portions 762, 764 which slope toward ends766, 768 of third and fourth arm 714, 716 respectively. The slopingportions accommodate the form of the lower vertebra against which theyare positioned. In the preferred embodiment, the sloping portions are ofabout 30°. However, it is to be understood that sloping portions whichare substantially greater and substantially less than 30° can beincluded and be within the spirit and scope of the invention.

Embodiment of FIGS. 79, 80, 80 a, 81, 82, 83, 83 a, 84, 85, 86 and 87

Another embodiment of the invention is shown in FIGS. 79-87 and includesimplant 800 (FIG. 86). Implant 800 includes a distracting unit 802 whichis shown in left side, plan, and right side views of FIGS. 79, 80 and81. A perspective view of the distraction unit is shown in FIG. 84. Thedistracting unit as can be seen in FIG. 80 includes a distracting body804, with longitudinal axis 805, which body 804 has a groove 806 and arounded or bulbous end 808 which assist in the placement of thedistracting body between adjacent spinous process so that an appropriateamount of distraction can be accomplished. Extending from thedistracting body 804 is a first wing 810 which in FIG. 80 issubstantially perpendicular to the distracting body 804. Such wingswhich are not perpendicular to the body are within the spirit and scopeof the invention. First wing 810 includes a upper portion 812 and alower portion 814. The upper portion 810 (FIG. 79) includes a roundedend 816 and a small recess 818. The rounded end 816 and the small recess818 in the preferred embodiment are designed to accommodate theanatomical form or contour of the L4 (for a L4-L5 placement) or L5 (fora L5-S1 placement) superior lamina of the vertebra. It is to beunderstood that the same shape or variations of this shape can be usedto accommodate other lamina of any vertebra. The lower portion 814 isalso rounded in order to accommodate in the preferred embodiment inorder to accommodate the vertebrae. The distracting unit furtherincludes a threaded bore 820 which in this embodiment accepts a setscrew 822 (FIG. 86) in order to hold a second wing 824 (FIGS. 82, 83) inposition as will be discussed hereinbelow.

The threaded bore 820 in this embodiment slopes at approximately 45°angle and intersects the slot 806. With the second wing 824 in position,the set screw 822 when it is positioned in the threaded bore 820 canengage and hold the second wing 824 in position in the slot 806.

Turning to FIGS. 82, 83 and 85, left side, plan and perspective views ofthe second wing 824 are depicted. The second wing 824 is similar indesign to the first wing. The second wing includes an upper portion 826and a lower portion 828. The upper portion includes a rounded end 830and a small recess 832. In addition, the second wing 824 includes a slot834 which mates with the slot 806 of the distracting unit 802. Thesecond wing 824 is the retaining unit of the present embodiment.

As can be seen in FIGS. 83 and 86, the second wing or retaining unit 824includes the upper portion 826 having a first width “a” and the lowerportion 828 having a second width “b”. In the preferred embodiment, thesecond width “b” is larger than first width “a” due to the anatomicalform or contour of the L4-L5 or L5-S1 laminae. As can be seen in FIG. 83a in second wing or retaining unit 824, the widths “a” and “b” would beincreased in order to, as described hereinbelow, accommodate spinousprocesses and other anatomical forms or contours which are of differentdimensions. Further, as appropriate, width “a” can be larger than width“b”. Thus, as will be described more fully hereinbelow, the implant caninclude a universally-shaped distracting unit 802 with a plurality ofretaining units 824, with each of the retaining units having differentwidths “a” and “b”. During surgery, the appropriately sized retainingunit 824, width with the appropriate dimensions “a” and “b” can beselected to match to the anatomical form of the patient.

FIG. 86 depicts an assembled implant 800 positioned adjacent to upperand lower laminae 836, 838 (which are shown in dotted lines) of theupper and lower vertebrae. The vertebrae 836, 838 are essentially belowthe implant 800 as shown in FIG. 86. Extending upwardly from thevertebrae 836, 838, and between the first and second wings 810, 824, arethe upper and lower spinous processes 840, 842. It is to be understoodthat in a preferred embodiment, the fit of the implant between thespinous processes can be such that the wings do not touch the spinousprocesses, as shown in FIG. 86, and be within the spirit and scope ofthe invention.

The implant 800 includes, as assembled, an upper saddle 844 and thelower saddle 846. The upper saddle 844 has an upper width identified bythe dimension “UW”. The lower saddle 846 has a lower width identified bythe dimension “LW”. In a preferred embodiment, the upper width isgreater than the lower width. In other embodiments, the “UW” can besmaller than the “LW” depending on the anatomical requirements. Theheight between the upper and lower saddles 844, 846 is identified by theletter “h”. These dimensions are carried over into FIG. 87 which is aschematic representation of the substantially trapezoidal shape which isformed between the upper and lower saddles. The table below gives setsof dimensions for the upper width, lower width, and height as shown inFIG. 87. This table includes dimensions for some variations of thisembodiment. Variation 1 2 3 Upper Width 8 7 6 Lower Width 7 6 5 Height10 9 8

For the above table, all dimensions are given in millimeters.

For purposes of surgical implantation of the implant 800 into a patient,the patient is preferably positioned on his side (arrow 841 points upfrom an operating table) and placed in a flexed (tucked) position inorder to distract the upper and lower vertebrae.

In a preferred procedure, a small incision is made on the midline of thespinous processes. The spinous processes are spread apart or distractedwith a spreader. The incision is spread downwardly toward the table, andthe distracting unit 802 is preferably inserted upwardly between thespinous processes 840 and 842 in a manner that maintains the distractionof spinous processes. The distracting unit 802 is urged upwardly untilthe distracting or bulbous end 808 and the slot 806 are visible on theother wide of the spinous process. Once this is visible, the incision isspread upwardly away from the table and the retaining unit or secondwing 824 is inserted into the slot 806 and the screw 822 is used tosecure the second wing in position. After this had occurred, theincisions can be closed.

An alternative surgical approach requires that small incisions be madeon either side of the space located between the spinous processes. Thespinous processes are spread apart or distracted using a spreader placedthrough the upper incision. From the lower incision, the distractingunit 802 is preferably inserted upwardly between the spinous processes840 and 842 in a manner that urges the spinous processes apart. Thedistracting unit 802 is urged upwardly until the distracting or bulbousend 808 and the slot 806 are visible through the second small incisionin the patient's back. Once this is visible, the retaining unit orsecond wing 824 is inserted into the slot 806 and the screw 822 is usedto secure the second wing in position. After this has occurred, theincisions can be closed.

The advantage of either of the above present surgical procedures is thata surgeon is able to observe the entire operation, where he can lookdirectly down onto the spinous processes as opposed to having to viewthe procedure from positions which are to the right and to the left ofthe spinous processes. Generally, the incision is as small as possibleand the surgeon is working in a bloody and slippery environment. Thus,an implant that can be positioned directly in front of a surgeon iseasier to insert and assemble than an implant which requires the surgeonto shift from side to side. Accordingly, a top-down approach, as anapproach along a position to anterior line is preferred so that allaspects of the implantation procedure are fully visible to the surgeonat all times. This aides in the efficient location of (i) thedistracting unit between the spinous processes, (ii) the retaining unitin the distracting unit, and (iii) finally the set screw in thedistracting unit.

FIG. 80 a shows an alternative embodiment of the distracting unit 802 a.This distracting unit 802 a is similar to distracting unit 802 in FIG.80 with the exception that the bulbous end 808 a is removable from therest of the distracting body 804 a as it is screwed into the threadedbore 809. The bulbous end 808 a is removed once the distracting unit 802a is positioned in the patient in accordance with the descriptionassociated with FIG. 86. The bulbous end 808 a can extend past thethreaded bore 820 by about 1 cm in a preferred embodiment.

Embodiment of FIGS. 88, 89, 90 and 91

Another embodiment of the invention is shown in FIGS. 88, 89, 90 and 91.In this embodiment, the implant is identified by the number 900. Otherelements of implant 900 which are similar to implant 800 are similarlynumbered but in the 900 series. For example, the distracting unit isidentified by the number 902 and this is in parallel with thedistracting unit 802 of the implant 800. The distracting body isidentified by the number 904 in parallel with the distracting body 804of the implant 800. Focusing on FIG. 90, the distracting unit 902 isdepicted in a perspective view. The distracting unit includes slot 906which is wider at the top than at the bottom. The reason for this isthat the wider upper portion of the slot 906, which is wider than thesecond wing 924 (FIG. 89), is used to, allow the surgeon to easily placethe second wing 924 into the slot 906 and allow the wedge-shaped slot906 to guide the second wing 924 to its final resting position. As canbe see in FIG. 91, in the final resting position, the largest portion ofthe slot 906 is not completely filled by the second wing 924.

The end 908 of implant 900 is different in that it is more pointed,having sides 909 and 911 which are provided at about 45° angles (otherangles, such as by way of example only, from about 30° to about 60° arewithin the spirit of the invention), with a small flat tip 913 so thatthe body 904 can be more easily urged between the spinous processes.

The distracting unit 902 further includes a tongue-shaped recess 919which extends from the slot 906. Located in the tongue-shaped recess isa threaded bore 920.

As can be seen in FIG. 89, a second wing 924 includes a tongue 948 whichextends substantially perpendicular thereto and between the upper andlower portions 926, 928. The tab 948 includes a bore 950. With thesecond wing 924 positioned in the slot 906 of the distracting unit 902and tab 948 positioned in recess 919, a threaded set screw 922 can bepositioned through the bore 950 and engage the threaded bore 920 inorder to secure the second wing or retaining unit 924 to the distractingunit 902. The embodiment 900 is implanted in the same manner asembodiment 800 previously described. In addition, as the bore 922 issubstantially perpendicular to the distracting body 904 (and notprovided at an acute angle thereto), the surgeon can even more easilysecure the screw in place from a position directly behind the spinousprocesses.

Embodiment of FIGS. 92, 92 a, 92 b, 93, 93 a, 93 b, 93 c, 93 d, 94, 94a, 94 b, 95, 95 a, and 96

Still a further embodiment of the invention is depicted in FIGS. 92, and92 a. In this embodiment, the implant 1000 as can be seen in FIG. 92 aincludes a central elongated body 1002 which has positioned at one endthereof a first wing 1004. Wing 1004 is similar to the first wingpreviously described with respect to the embodiment of FIG. 88. Bolt1006 secures wing 1004 to body 1002 in this embodiment. Bolt 1006 isreceived in a bore of the body 1002 which is along the longitudinal axis1008 of body. It is to be understood that in this embodiment, the firstunit is defined by the central body 1002, the first wing 1004, and theguide 1010.

Alternatively, the first wing can be secured to the central body with apress fit and detent arrangement as seen in FIG. 93 c. In thisarrangement, the first wing has a protrusion 1040 extending preferablyabout perpendicularly from the first wing, with a flexible catch 1042.The protrusion and flexible catch are press fit into a bore 1044 of thecentral body with the catch received in a detent 1046.

In yet another alternative embodiment, the first wing can be designed asshown in FIG. 93 d with the protrusion directed substantially parallelto the first wing from a member that joins the first wing to theprotrusion. Thus in this embodiment, the first wing is inserted into thebody along the same direction as the second wing is inserted.

Positioned at the other end of the central body 1002 is a guide 1010. Inthis particular embodiment, guide 1010 is essentiallytriangularly-shaped so as to be a pointed and arrow-shaped guide.Alternatively, guide 1010 could be in the shape of a cone with lateraltruncated sides along the longitudinal axis 1008. Guide 1010 includes arecess 1012 having a threaded bore 1014. Recess 1012 is for receiving asecond wing 1032 as will be described hereinbelow.

Additionally, it is also to be understood that the guide 1010 can bebulbous, cone-shaped, pointed, arrow-shaped, and the like, in order toassist in the insertion of the implant 1000 between adjacent spinousprocesses. It is advantageous that the insertion technique disturb aslittle of the bone and surrounding tissue or ligaments as possible inorder to (1) reduce trauma to the site and facilitate early healing, and(2) not destabilize the normal anatomy. It is to be noted that with thepresent embodiment, there is no requirement to remove any of the bone ofthe spinous processes and depending on the anatomy of the patient, theremay be no requirement to remove or sever ligaments and tissuesimmediately associated with the spinous processes.

The implant 1000 further includes a sleeve 1016 which fits around and isat least partially spaced from the central body 1002. As will beexplained in greater detail below, while the implant may be comprised ofa bio-compatible material such as titanium, the sleeve is comprisedpreferably of a super-elastic material which is by way of example only,a nickel titanium material (NiTi), which has properties which allow itto withstand repeated deflection without fatigue, while returning to itsoriginal shape. The sleeve could be made of other materials, such as forexample titanium, but these materials do not have the advantages of asuper-elastic material.

FIG. 93 a is a cross-section through the implant 1000 depicting thecentral body 1002 and the sleeve 1016. As can be seen from thecross-section of FIG. 93 a in a preferred embodiment, both the centralbody 1002 and the sleeve 1016 are substantially cylindrical and oval orecliptically-shaped. An oval or elliptical shape allows more of thespinous process to be supported by the sleeve, thereby distributing theload between the bone and the sleeve more evenly. This reduces thepossibility of fracture to the bone or bone resorption. Additionally, anoval or elliptical shape enhances the flexibility of the sleeve as themajor axis of the sleeve, as described below, is parallel to thelongitudinal direction of the spinous process. However, other shapessuch as round cross-sections can come within the spirit and scope of theinvention.

In this particular embodiment, the central body 1002 includes elongatedgrooves 1018, along axis 1008, which receives elongated spokes 1020extending from the internal surface of the cylinder 1016.

In a preferred embodiment, both the cross-section of the central bodyand the sleeve have a major dimension along axis 1022 and a minordimensional along axis 1024 (FIG. 93 a). The spokes 1020 are along themajor dimension so that along the minor dimension, the sleeve 1016 canhave its maximum inflection relative to the central body 1002. It is tobe understood that the central body along the minor dimension 1024 canhave multiple sizes and can, for example, be reduced in thickness inorder to increase the ability of the sleeve 1016 to be deflected in thedirection of the central body 1002.

Alternatively as can be seen in FIG. 93 b, the central body 1002 caninclude the spokes 1020 and the sleeve 1016 can be designed to includethe grooves 1018 in order to appropriately space the sleeve 1016 fromthe central body 1002.

In other embodiments, the sleeve can have minor and major dimensions asfollows: Minor Dimension Major Dimension 6 mm   10 mm 8 mm 10.75 mm  12mm    14 mm 6 mm 12.5 mm 8 mm 12.5 mm 10 mm  12.5 mm

In one preferred embodiment, said sleeve has a cross-section with amajor dimension and a minor dimension and said major dimension isgreater than said minor dimension and less than about two times saidminor dimension. In said embodiment, said guide has a cross-sectionwhich is adjacent to said sleeve with a guide major dimension aboutequal to said sleeve major dimension and a guide minor dimension aboutequal to said sleeve minor dimension. Further in said embodiment, saidguide extends from said central body with a cross-section which reducesin size in a direction away from said central body.

In another preferred embodiment, said guide is cone-shaped with a baselocated adjacent to said sleeve. Further, said guide has a basecross-section about the same as the oval cross-section of said sleeve.

Thus, from the above, it is evident that preferably a major dimension ofthe sleeve correspond with a major dimension of the central body and aminor dimension of the sleeve corresponds with a minor dimension of thecentral body. Additionally, it is evident that the major dimension ofthe sleeve 1016 is substantially perpendicular to a major dimension ofthe first wing 1004 along longitudinal axis 1030 (FIG. 92 a). This is sothat as discussed above, when the implant 1000 is properly positionedbetween the spinous processes, a major portion of the sleeve comes incontact with both the upper and lower spinous processes in order todistribute the load of the spinous processes on the sleeve 1016 duringspinal column extension.

As indicated above, the preferred material for the sleeve 1016 is asuper-elastic material and more preferably one comprised of an alloy ofnickel and titanium. Such materials are available under the trademarkNitinol. Other super-elastic materials can be used as long as they arebio-compatible and have the same general characteristics ofsuper-elastic materials. In this particular embodiment, a preferredsuper-elastic material is made up of the following composition ofnickel, titanium, carbon, and other materials as follows: Nickel 55.80%by weight Titanium 44.07% by weight Carbon  <0.5% by weight Oxygen <0.5% by weight

In particular, this composition of materials is able to absorb about 8%recoverable strain. Of course, other materials which can absorb greaterand less than 8% can come within the spirit and scope of the invention.This material can be repeatably deflected toward the central body andreturned to about its original shape without fatigue. Preferably andadditionally, this material can withstand the threshold stress with onlya small amount of initial deforming strain and above the thresholdstress exhibit substantial and about instantaneous deformation strainwhich is many times the small amount of initial deforming strain. Such acharacteristic is demonstrated in FIG. 118 where it is shown that abovea certain threshold stress level, deformation strain is substantiallyinstantaneous up to about 8%. FIG. 118 shows a loading and unloadingcurve between stress and deformation strain for a typical type ofsuper-elastic material as described above.

Preferably, the above super-elastic material is selected to allowdeformation of up to about, by way of example only, 8%, at about 20 lbs.to 50 lbs. force applied between a spinous processes. This would cause asleeve to deflect toward the central body absorbing a substantial amountof the force of the spinous processes in extension. Ideally, the sleevesare designed to absorb 20 lbs. to 100 lbs. before exhibiting thesuper-elastic effect (threshold stress level) described above. Further,it is possible, depending on the application of the sleeve and theanatomy of the spinal column and the pairs of spinous processes for aparticular individual, that the sleeve can be designed for a preferablerange of 20 lbs. to 500 lbs. of force before the threshold stress levelis reached. Experimental results indicate that with spinous processes ofan older individual, that at about 400 pounds force, the spinous processmay fracture. Further, such experimental results also indicate that withat least 100 pounds force, the spinous process may experience somecompression. Accordingly, ideally the super-elastic material is designedto deform or flex at less than 100 pounds force.

In a preferred embodiment, the wall thickness of the sleeve is about 1mm or 40/1000 of an inch (0.040 in.). Preferably the sleeve is designedto experience a combined 1 mm deflection. The combined 1 mm deflectionmeans that there is ½ mm of deflection at the top of the minor dimensionand a ½ mm deflection at the bottom of the minor dimension. Bothdeflections are toward the central body.

In a particular embodiment where the sleeve is more circular incross-section, with an outer dimension of 0.622 in. and a wall thicknessof 0.034 in., a 20 lb. load causes a 0.005 in. deflection and a 60 lb.load causes a 0.020 in. deflection (approximately ½ mm). A 100 lb. loadwould cause a deflection of about 0.04 in. or approximately 1 mm.

Thus in summary, the above preferred super-elastic material means thatthe sleeve can be repeatedly deflected and returned to about itsoriginal shape without showing fatigue. The sleeve can withstand athreshold stress with a small amount of deforming strain and at aboutsaid threshold stress exhibit about substantially instantaneousdeformation strain which is many times the small amount of the formingstrain. In other words, such super-elastic qualities mean that thematerial experiences a plateau stress where the material supports aconstant force (stress) over very large strain range as exhibited inFIG. 118.

It is to be understood that for this particular embodiment, bar stock ofthe super-elastic material is machined into the appropriate form andthen heat treated to a final temperature to set the shape of thematerial by increasing the temperature of the material to 932°Fahrenheit and holding that temperature for five (5) minutes and thenquickly quenching the sleeve in water. It is also to be understood thatpreferably the present nickel titanium super-elastic alloy is selectedto have a transition temperature A_(f) of about 59° Fahrenheit (15° C.).Generally for such devices the transition temperature can be between 15°C. to 65° C. (59° F. to 149° F.), and more preferably 10° C. to 40° C.(50° F. to 104° F.). Preferably, the material is maintained in the bodyabove the transition temperature in order to exhibit optimal elasticityqualities.

Alternatively, and preferably, the sleeve can be fabricated by wireElectrical Discharge Machining (EDM) rather than machined. Additionally,the sleeve can be finished using a shot blast technique in order toincrease the surface strength and elasticity of the sleeve.

Top and side views of the second wing 1032 are shown in FIGS. 94 and 95.Second wing 1032 as in several past embodiments includes a tab 1034 witha bore 1036 which aligns with the bore 1014 of the guide 1010. In thisparticular embodiment, the second wing 1032 includes a cut-out 1038which is sized to fit over the guide 1010, with the tab 1034 resting inthe recess 1012 of the guide 1010.

An alternative configuration of the second wing 1032 is depicted in FIG.94 a. In this configuration, the second wing 1032 is held at acute anglewith respect to the tab 1034. This is different from the situation inthe embodiment of FIGS. 94 and 95 where the second wing is substantiallyperpendicular to the tab. For the embodiment of the second wing in FIG.94 a, such embodiment will be utilized as appropriate depending on theshape of the spinous processes.

With respect to the alternative second wing 1032 depicted in FIGS. 94 band 95 a, elongated tab 1034 has a plurality of closely positioned bores1036. The bores, so positioned, appear to form a scallop shape. Eachindividual scallop portion of the bore 1036 can selectively hold thebolt in order to effectively position the second wing 1032 in threedifferent positions relative to the first wing 1004. The cut-out 1038(FIG. 95 a of this alternative embodiment) is enlarged over that of FIG.95 as in a position closest to the first wing 1004, the second wing 1032is immediately adjacent and must conform to the shape of the sleeve1016.

Embodiment of FIG. 97

Implant 1050 of FIG. 97 is similar to the implant 1000 in FIG. 92 withthe major difference being that a second wing is not required. Theimplant 1050 includes a central body as does implant 1000. The centralbody is surrounded by a sleeve 1016 which extends between a first wing1004 and a guide 1010. The guide 1010 in this embodiment issubstantially cone-shaped without any flats and with no bore as there isno need to receive a second wing. The sleeve and the central body aswell as the first wing and guide act in a manner similar to those partsof the implant 1000 in FIG. 92. It is to be understood a cross-sectionof this implant 1050 through sleeve 1016 can preferably be like FIG. 93a. This particular embodiment would be utilized in a situation where itwas deemed impractical or unnecessary to use a second wing. Thisembodiment has the significant advantages of the sleeve being comprisedof super-elastic alloy materials as well as the guide being utilized toguide the implant between spinous processes while minimizing damage tothe ligament and tissue structures found around the spinous processes.

Embodiment of FIG. 98

Implant 1060 is depicted in FIG. 98. This implant is similar to theimplants 1000 of FIG. 92 and the implant 1050 of FIG. 97, except thatthis implant does not have either first or second wings. Implant 1060includes a sleeve 1016 which surrounds a central body just as centralbody 1002 of implant 1000 in FIG. 93. It is to be understood that across-section of this implant 1060 through sleeve 1016 can preferably belike FIG. 93 a. Implant 1060 includes a guide 1010 which in thispreferred embodiment is cone-shaped. Guide 1010 is located at one end ofthe central body. At the other end is a stop 1062. Stop 1062 is used tocontain the other end of the sleeve 1016 relative to the central body.This embodiment is held together with a bolt such as bolt 1006 of FIG.93 that is used for the immediate above two implants. For the implant1060 of FIG. 98, such a device would be appropriate where the anatomybetween the spinous processes was such that it would be undesirable touse either a first or second wing. However, this embodiment affords allthe advantageous described hereinabove (FIGS. 92 and 97) with respect tothe guide and also with respect to the dynamics of the sleeve.

Embodiment of FIGS. 99 and 100

FIGS. 99 and 100 depict an implant system 1070. Implant system 1070includes a sleeve 1072 which is similar to and has the advantageous ofsleeve 1016 of the embodiment in FIG. 92. Sleeve 1072 does not, however,have any spokes. Additionally, implant system 1070 includes an insertiontool 1074. Insertion tool 1074 includes a guide 1076 which in apreferred embodiment is substantially cone-shaped. Guide 1076 guides theinsertion of the sleeve 1072 and the insertion tool 1074 betweenadjacent spinous processes. The insertion tool 1074 further includes acentral body 1078, a stop 1080, and a handle 1082. The guide 1076 at itsbase has dimensions which are slightly less than the internal dimensionsof the sleeve 1074 so that the sleeve can fit over the guide 1076 andrest against the stop 1080. The tool 1074 with the guide 1076 is used toseparate tissues and ligaments and to urge the sleeve 1072 in the spacebetween the spinous processes. Once positioned, the guide insertion tool1074 can be removed leaving the sleeve 1072 in place. If desired, afterthe sleeve is positioned, position maintaining mechanisms such asspringy wires 1084 made out of appropriate material such as thesuper-elastic alloys and other materials including titanium, can beinserted using a cannula through the center of the sleeve 1072. Onceinserted, the ends of the retaining wires 1084 (FIG. 99) extend out ofboth ends of the sleeve 1072, and due to this springy nature, bent at anangle with respect to the longitudinal axis of the sleeve 1072. Thesewires help maintain the position of the sleeve relative to the spinousprocesses.

Embodiment of FIGS. 101, 102, 102 a, 103, 104, 105, 106, and 107

Another embodiment of the invention can be seen in FIG. 101 whichincludes implant 1100. Implant 1100 has many similar features that areexhibited with respect to implant 1000 in FIG. 92. Accordingly, elementswith similar features and functions would be similarly numbered.Additionally, features that are different from implant 1100 can be, ifdesired, imported into and become a part of the implant 1000 of FIG. 92.

As with implant 1000, implant 1100 includes a central body 1002 (FIG.102) with a first wing 1004 and a bolt 1006 which holds the first wingand the central body together. In this particular embodiment, thecentral body is made in two portions. The first portion 1102 is in theshape of a truncated cone with an oval or elliptical base and a secondportion 1104 includes a cylindrical central portion with a distal end inthe shape of a truncated cone 1103 with an oval or elliptical base. Inaddition, in this particular embodiment, formed with the central body isthe guide 1010 which has an oval or elliptical base. Bolt 1006 is usedto secure the first wing through the second portion 1104 with the firstportion 1102 held in-between. In this particular embodiment, the guide1010 in addition to including recess 1012 and bore 1014 includes agroove 1106 which receives a portion of the second wing 1032.

In this particular embodiment, the sleeve 1016 is preferably oval orelliptical in shape as can be seen in FIG. 102 a. The central body canbe oval, elliptical or circular in cross-section, although other shapesare within the spirit and scope of the invention. The sleeve 1016 heldin position due to the fact that the truncated conical portion 1102 andthe corresponding truncated conical portion 1103 each have a base thatis elliptical or oval in shape. Thus, the sleeve is held in position sothat preferably the major dimension of the elliptical sleeve issubstantially perpendicular to the major dimension of the first wing. Itis to be understood that if the first wing is meant to be put beside thevertebrae so that the first wing is set at an angle other thanperpendicular with respect to the vertebrae and that the sleeve may beheld in a position so that the major dimension of the sleeve is at anangle other than perpendicular to the major dimension of the first wingand be within the spirit and scope of the invention. This could beaccomplished by tightening bolt 1006 with the first wing 1004 and sleeve1016 so positioned. In such a configuration, the major dimension of thesleeve would be preferably positioned so that it is essentially parallelto the length of the adjacent spinous processes. So configured, theelliptical or oval shape sleeve would bear and distribute the load moreevenly over more of its surface.

It is to be understood that the sleeve in this embodiment has all thecharacteristics and advantages described hereinabove with respect to theabove-referenced super-elastic sleeves.

The second wing as discussed above, can come in a variety of shapes inorder to provide for variations in the anatomical form of the spinousprocesses. Such shapes are depicted in FIGS. 103, 104, 105, 106, and107. In each configuration, the second wing 1032 has a upper portion1108 and a lower portion 1110. In FIG. 104, the lower portion is thickerthan the upper portion in order to accommodate the spinous process,where the lower spinous process is thinner than the upper spinousprocess. In FIG. 105, both the upper and lower portions are enlargedover the upper and lower portions of FIG. 103 to accommodate both theupper and lower spinous processes being smaller. That is to say that thespace between the upper and lower portions of the first and second wingsare reduced due to the enlarged upper and lower portions of the secondwing.

Alternative embodiments of second wings, as shown in FIGS. 104 and 105,are depicted in FIGS. 106 and 107. In these FIGS. 106 and 107, thesecond wing 1032 accommodates the same anatomical shape and size of thespinous processes as does the second wing in FIGS. 104 and 105respectively. However, in the embodiments of the second wing 1032 ofFIGS. 106 and 107, substantial masses have been removed from the wings.The upper and lower portions 1108 and 1110 are essentially formed orbent in order to extend from the central portion 1112 of the second wing1032.

It is to be understood that in this embodiment, if desired, the secondwing may not have to be used, depending on the anatomy of the spinalcolumn of the body, and this embodiment still has the significantadvantages attributable to the guide 1010 and the functionality of thesleeve 1016.

Embodiment of FIGS. 108, 109, and 110

The implant 1120 as shown in FIGS. 108 and 109, is similar to implant1100 which is in turn similar to implant 1000. Such similar details havealready been described above and reference here is made to the uniqueorientation of the first and second wings 1122 and 1124. These wingshave longitudinal axis 1126 and 1128 respectfully. As can be seen inthese figures, the first and second wings 1122, 1124 have been rotatedso that they both slope inwardly and if they were to continue out of thepage of the drawing of FIG. 108, they would meet to form an A-framestructure as is evident from the end view of FIG. 109. In thisparticular embodiment, as can be seen in FIGS. 109 and 110, the tab 1034is provided an acute angle to the remainder of the second wing 1124.Further, the groove 1018 formed in the implant is sloped in order toaccept the second wing 1124. Accordingly, this present implant 1120 isparticularly suited for an application where the spinous process iswider adjacent to the vertebral body and then narrows in size at leastsome distance distally from the vertebral body. It is to be understoodthat a cross-section of this implant 1120 through sleeve 1016 canpreferably be like FIG. 93 a.

Embodiment of FIGS. 111, 112, 113, 114, 115, 116, and 117

An additional embodiment of the implant 1150 is shown in FIG. 111.Implant 1150 has features similar to those described with respect toFIG. 94 b.

Implant 1150 includes a central body 1152 with a first wing 1154, wherecentral body 1152 includes elongated groove 1156 which extends to theguide 1158. A screw 1160 is received in a threaded bore located in theelongated groove 1156.

The second wing 1162 includes a central body 1164 which is substantiallyperpendicular to the second wing 1162.

The central body 1164 includes a plurality of bores 1166 providedtherein. These bores are formed adjacent to each other in order todefine a plurality of scallops, each scallop capable of retaining bolt1160 therein. As can be seen in FIG. 114, the second wing includes acut-out 1168 such that with the central body 1164 of the second wingreceived in the groove 1156 of the central body associated with thefirst wing, the remainder of the second wing is received over thecentral body 1152 of the implant 1150. With this implant 1150, thedistance between the first and second wings can be adjusted byselectively placing the bolt 1160 through one of the five specifiedbores defined by the scalloped plurality of bores 1166. Accordingly,FIG. 112 depicts the implant where the first and second wings are widestapart in order to accommodate spinous processes of greater thickness.FIG. 111 shows the middle position between the first and second wings inorder to accommodate average size spinous processes.

It is to be understood that preferably during the surgical process, thecentral body 1152 is urged between spinous processes. After this hasoccurred, the second wing is guided by the other sides of the spinousprocesses from a path which causes the plane of the second wing to movesubstantially parallel to the plane of the first wing until the centralbody 1164 associated with the second wing 1162 is received in the grooveof 1156 of the central body 1152 associated with the first wing 1154.After this has occurred, the bolt 1160 is positioned through alignedbores associated with the second wing 1162 and the central body 1152 inorder to secure the second wing to the central body.

While embodiment 1150 does not depict a sleeve such as sleeve 1016, sucha sleeve 1016 could be placed over body 1152 and be within the spirit ofthe invention.

INDUSTRIAL APPLICABILITY

From the above, it is evident that the present invention can be used torelieve pain caused by spinal stenosis in the form of, by way of exampleonly, central canal stenosis or foraminal (lateral) stenosis. Theseimplants have the ability to flatten the natural curvature of the spineand open the neural foramen and the spacing between adjacent vertebra torelieve problems associated with the above-mentioned lateral and centralstenosis. Additionally, the invention can be used to relieve painassociated with facet arthropathy. The present invention is minimallyinvasive and can be used on an outpatient basis.

Additional aspects, objects and advantages of the invention can beobtained through a review of the appendant claims and figures.

It is to be understood that other embodiments can be fabricated and comewithin the spirit and scope of the claims.

1. An apparatus, comprising: a body having a central portion, a firstarm, a second arm, a third arm and a fourth arm, the central portion ofthe body configured to be disposed between adjacent spinous processes,the first arm and the third arm at a first side of the body, the firstarm having a length greater than a length of the third arm such that thefirst arm is moveable through a space between the adjacent spinousprocesses and such that the third arm is moveable through the space toposition the central body between the adjacent spinous processes, asecond arm and a fourth arm at a second side of the body opposite of thefirst side of the body.
 2. The apparatus of claim 1, wherein the secondarm has a length greater than a length of the fourth arm.
 3. Theapparatus of claim 1, wherein: the length of the third arm is less thanthe length of the first arm such that the adjacent spinous processes aredistracted when the first arm is moved through a space between theadjacent spinous processes and such that the central portion of the bodyis positioned between the spinous processes when the third arm is movedthrough the space between the adjacent spinous processes.
 4. Theapparatus of claim 1, wherein the central portion of the body defines abore.
 5. The apparatus of claim 1, wherein the central portion of thebody defines a bore so that the central portion of the body has amodulus of elasticity compatible with a modulus of elasticity of bone.6. The apparatus of claim 1, wherein the central portion of the body hasa modulus of elasticity compatible with a modulus of elasticity of bone.7. The apparatus of claim 1, wherein the central portion of the body hasas modulus of elasticity approximately twice a modulus of elasticity ofbone.
 8. An apparatus, comprising: a body having a central portion, afirst arm, a second arm, a third arm and a fourth arm, the first arm andthe fourth arm being longer than the central portion, the second arm andthe third arm being no longer than the central portion, the third armhaving a length less than a length of the first arm such that the firstarm is moveable through a space between the adjacent spinous processesand such that the third arm is moveable through the space to positionthe central portion of the body between the spinous processes thecentral portion, the first arm and the third arm collectively defining afirst saddle configured to receive a first spinous process from adjacentspinous processes, and the central portion, the second arm and thefourth arm collectively defining a second saddle configured to receive asecond spinous process from the adjacent spinous processes.
 9. Theapparatus of claim 8, wherein: the third arm has a length less than alength of the first arm such that the adjacent spinous processes aredistracted when the first arm is moved through a space between theadjacent spinous processes and such that the central portion of the bodyis positioned between the spinous processes when the third arm is movedthrough the space between the adjacent spinous processes.
 10. Theapparatus of claim 8, wherein the central portion of the body defines abore.
 11. The apparatus of claim 8, wherein the central portion of thebody defines a bore so that the central portion of the body has amodulus of elasticity compatible with a modulus of elasticity of bone.12. The apparatus of claim 8, wherein the central portion of the bodyhas a modulus of elasticity compatible with a modulus of elasticity ofbone.
 13. The apparatus of claim 8, wherein the central portion of thebody has a modulus of elasticity approximately twice a modulus ofelasticity of bone.
 14. A method, comprising: accessing a first spinousprocess and a second spinous process from a first side, the firstspinous process and the second spinous process being adjacent spinousprocesses; inserting a first arm of an implant between the first spinousprocess and the second spinous process from the first side to a secondside of the adjacent spinous processes opposite the first side, theimplant having a central portion, a second arm, a third arm and a fourtharm, the first arm and the third arm being on a first side of thecentral portion, the second arm and the fourth arm being on a secondside of the central portion opposite the first side of the centralportion; and inserting the third arm between the first spinous processand the second spinous process from the first side to the second side ofthe adjacent spinous processes such that the first spinous process ispositioned between the first arm and the second arm, the second spinousprocess is positioned between the third arm and the fourth arm and thecentral portion is positioned between the adjacent spinous processes.15. The method of claim 14, further comprising: making an incisionlaterally between the first spinous process and the second spinousprocess.
 16. The method of claim 14, further comprising: making anincision laterally between the first spinous process and the secondspinous process; and distracting, before the inserting the third arm,the first spinous process away from the second spinous process to definea distance between adjacent spinous processes such that the third armpasses through the incision between the first spinous process and thesecond spinous process.
 17. The method of claim 14, further comprising:making an incision laterally between the first spinous process and thesecond spinous process; and distracting, before the inserting the thirdarm, the first spinous process away from the second spinous processusing a distraction tool to define a distance between adjacent spinousprocesses such that the third arm passes through the incision betweenthe first spinous process and the second spinous process.
 18. The methodof claim 14, further comprising: making an incision laterally betweenthe first spinous process and the second spinous process; anddistracting, before the inserting the third arm, the first spinousprocess away from the second spinous process using the implant to definea distance between adjacent spinous processes such that the third armpasses through the incision between the first spinous process and thesecond spinous process.
 19. The method of claim 14, further comprising:making an incision laterally between the first spinous process and thesecond spinous process; and distracting, before the inserting the thirdarm, the first spinous process away from the second spinous processusing the implant and a distraction tool to define a distance betweenadjacent spinous processes such that the third arm passes through theincision between the first spinous process and the second spinousprocess.
 20. The method of claim 14, wherein the central portion of theimplant defines a bore.
 21. The method of claim 14, wherein the centralportion of the implant defines a bore so that the central portion of theimplant has a modulus of elasticity compatible with a modulus ofelasticity of bone.
 22. The method of claim 14, wherein the centralportion of the implant has a modulus of elasticity compatible with amodulus of elasticity of bone.
 23. The method of claim 14, wherein thecentral portion of the implant has as modulus of elasticityapproximately twice a modulus of elasticity of bone.
 24. A method,comprising: positioning an implant between first and second adjacentspinous processes in order to relieve pain associated with the spinewherein the implant comprises a first saddle for receiving the firstspinous process and a second saddle for receiving the second spinousprocess and wherein the first saddle lies between a first arm and asecond arm and the second saddle lies between a third arm and a fourtharm, and wherein the method includes the steps of: accessing a firstspinous process and a second spinous process from a first side, thefirst spinous process and the second spinous process being adjacentspinous processes; inserting a first arm of an implant between the firstspinous process and the second spinous process from the first side to asecond side of the adjacent spinous processes opposite the first side,the implant having a central portion, a second arm, a third arm and afourth arm, the first arm and the third arm being on a first side of thecentral portion, the second arm and the fourth arm being on a secondside of the central portion opposite the first side of the centralportion; and inserting the third arm between the first spinous processand the second spinous process from the first side to the second side ofthe adjacent spinous processes until the first spinous process ispositioned in the first saddle and the second spinous process ispositioned in the second saddle.
 25. The method of claim 24, furthercomprising: making an incision laterally between the first spinousprocess and the second spinous process.
 26. The method of claim 24,further comprising: making an incision laterally between the firstspinous process and the second spinous process; and distracting, beforethe inserting the third arm, the first spinous process away from thesecond spinous process to define a distance between adjacent spinousprocesses such that the third arm passes through the incision betweenthe first spinous process and the second spinous process.
 27. The methodof claim 24, further comprising: making an incision laterally betweenthe first spinous process and the second spinous process; anddistracting, before the inserting the third arm, the first spinousprocess away from the second spinous process using a distraction tool todefine a distance between adjacent spinous processes such that the thirdarm passes through the incision between the first spinous process andthe second spinous process.
 28. The method of claim 24, furthercomprising: making an incision laterally between the first spinousprocess and the second spinous process; and distracting, before theinserting the third arm, the first spinous process away from the secondspinous process using the implant to define a distance between adjacentspinous processes such that the third arm passes through the incisionbetween the first spinous process and the second spinous process. 29.The method of claim 24, further comprising: making an incision laterallybetween the first spinous process and the second spinous process; anddistracting, before the inserting the third arm, the first spinousprocess away from the second spinous process using the implant and adistraction tool to define a distance between adjacent spinous processessuch that the third arm passes through the incision between the firstspinous process and the second spinous process.
 30. The method of claim24, wherein the central portion of the implant defines a bore.
 31. Themethod of claim 24, wherein the central portion of the implant defines abore so that the central portion of the implant has a modulus ofelasticity compatible with a modulus of elasticity of bone.
 32. Themethod of claim 24, wherein the central portion of the implant has amodulus of elasticity compatible with a modulus of elasticity of bone.33. The method of claim 24, wherein the central portion of the implanthas as modulus of elasticity approximately twice a modulus of elasticityof bone.